Plastic horse shoe and method of applying to hoof



Feb. 10, 1970 F M CLARK 3,494,422

PLASTIC HORSE SHOE AND METHOD OF APPLYING T0 HOOF Filed Jan. 16, 1967 2Sheets-Sheet 1 INVENTOR.

FRANK M. CLARK ATTORNEYS Feb. 10, 1970 v F. M. CLARK 3,494,422

PLASTIC HORSE SHOE AND METHOD OF APPLYING TO ROOF Filed Jan. 16, 1967 2Sheets-Sheet 2 United States Patent Office 3,494,422 Patented Feb. 10,1970 US. Cl. 168-4 8 Claims ABSTRACT OF THE DISCLOSURE The applicationdiscloses a novel shoe for hoofed animals, formed of a synthetic resinmaterial, such as an elastomeric polyurethane plastic, that may be castto shape and size while being sufficiently flexible for close fitting tothe hoof. The shoe exhibits resistance to wear and a'braison comparableto iron and other metallic shoes. It includes calks and cleats that maybe trimmed, a protective flange for the front edge of the hoof, and achannel for lubricant beneficial to the hoof. A method and apparatus forapplying the shoes without nails is also disclosed. The shape andeffective size of the shoe can be adjusted by the shortening of a heelcrossbar.

BRIEF SUMMARY OF THE INVENTION This application relates to so-calledshoes for hoofed animals, particularly horses.

For many centuries the conventional material for shoeing horses, inparticular, has been a form of iron or steel. The shoes are normallyfitted to the hoof while hot, and a great amount of skill is required toachieve the proper fitting without injury to the hoof. There have beenknown a few instances where metal shoes have been fitted and adjustedWhile cold, but this is a difficult task, and few shoers have either thetime or the skill to achieve the proper fit with a cold metal shoe.

In this art, there are a number of factors which must be taken intoconsideration in selecting a proper shoe and fitting it to the hoof. Thetype of service in which the animal will be used is a consideration inselecting the weight and style of shoe to be used, and the gait of theparticular animal, and to some extent even its habits, must also betaken into consideration. For example, it is recognized that shoes forracing thoroughbred horses are desirably light and thin, their mainpurpose being to help the horse to grip the track. Harness horses mayrequire a number of different types of shoes in order to adjust theanimals stride or alter its gait, and jumping horses usually require arather large calk on the hind shoes. The same horse may have to be shoddifferently when the type of work or use to which it is put changes.

Particularly where shoes are fitted and selected to help correct gaittroubles, the proper shaping and fitting is most important. It ispossible to correct gait problems such as forging, interfering, andspeedy-cutting with proper shoeing, and it is also possible to enable ahorse afflicted with founder to walk and run reasonably well with propershoeing. The fact remains, however, that metal shoes must in all casesbe fitted hot, they are nailed to the hoof, and the metal shoes willabrade and thus be formed during use with sharp edges which can increasethe injuries resulting where gait troubles occur. Also, metal shoes willtransmit any shock directly to the hoof, with practically no shockabsorption, and the possibility of injury from loosened nails, or evenimproperly applied nails, is well-known.

Rubber shoes have been known for some time, one of their chief usesbeing on horses used in the past to pull delivery trucks, especiallyover hard surface streets where the metal shoes made objectionable noiseat night or in the early morning. Generally speaking, however, therubber shoes did not have either the desirable wear or pullingcharacteristics, but were considered a compromise to give the horseadequate footing for its task while minimizing noise. More recently,some shoes have been available made of synthetic resin material, such asnylon, however these shoes are essentially direct replicas of the ironshoes, and it appears from experience with them that the wearcharacteristics are unsatisfactory, and they do not incorporate thedesirable and novel features disclosed herein.

The object of the present invention is to provide a novel shoe forhoofed animals, particularly horses, which is formed of a syntheticresin material, preferably an elastomeric polyurethane plastic, that maybe cast to the desired shape while still being sufficiently flexible tofacilitate close fitting of the shoe to the hoof, and at the same timeproviding such a shoe which will wear and last as well as iron and othermetallic shoes, even under hard use as in racing; to provide a horseshoewhich achieves some shock absorption and thereby relieves the horse fromsome of the impact on its hooves and legs during hard running, whilestill maintaining satisfactory wear such that the shoes do not need tobe replaced after an objectionably short time of use; to provide such ahorseshoe which may be trimmed, shaped, and closely fitted, and appliedto the hoof with or without the use of nails, thereby eliminating theobjectionable features of nails previously used; to provide such ahorseshoe which incorporates a protective flange that minimizes thetendency of the hoof edge to cut when it overreaches or interfers duringa particular gait; to provide such a horseshoe in which the hoof surfaceof the shoe can be closely fitted to the bearing surface of the hoof,and wherein the hoof surface of the shoe incorporates a channel forholding a quantity of lubricant or the like which is beneficial to thehorny structure of the hoof; and to provide a novel method and apparatusfor shoeing horses and like animals.

Other objects and advantages of the invention will be apparent from thefollowing description, the accompanying drawings and the appendedclaims.

In the drawings FIG. 1 is an elevational view of the bottom or groundsurface of a horseshoe provided by the invention;

FIG. 2 is an elevational view of the top or hoof surface of the shoeshown in FIG. 1;

FIG. 3 is an edge view of the shoe shown in FIG. 1, as seen from therear, or bottom of FIG. 1;

FIG. 4 is an edge view of the front of the shoe, as seen from the top ofFIGS. 1 and 2;

FIG. 5 is a partial sectional view taken along lines 55 in FIG. 2;

FIG. 6 is an enlarged partial sectional view taken along lines 66 inFIG. 1;

FIG. 7 is a bottom elevational view of a modified form of shoe, omittingthe cleats and incorporating calks at the rear;

FIG. 8 is an enlarged parallel sectional view taken on lines 88 of FIG.7;

FIG. 9 is a perspective view showing a tool provided by the inventionused to apply one of the novel shoes to a hoof; and

FIG. 10 is a bottom view of the tool holding a shoe on the hoof, withthe open position of the tool shown in dot-dash lines.

Referring to the drawings, which illustrate preferred embodiments of theinvention, and particularly with reference to FIGS. l6, the shoe provideby the invention comprise the body 10 cast or molded of a synthetic,wear resistant, resilient resinous material. This material is selectedto provide a resistance to abrasion, even under conditions of hard usesuch as on racing or jumping horses, while still being suflicientlyresilient to provide shock absorption which is beneficial to the hooves,legs and leg joints of the animal.

Particularly under racing conditions, substantial shock is imparted tothe legs and leg joints of a horse. Conventional metal shoes, usuallyformed of cast iron, provide no appreciable shock absorption, but ratherdue to their hard and rigid structure, they tend to transfer the shockdirectly to the hoof and leg each time the hoof engages the ground.Metal shoes are difficult to fit, must be heated to a relatively hightemperature for this purpose, and even then are difiicult to shape. Animportant feature of this invention is the discovery that certainmaterials are particularly suitable for use as horseshoes withoutsacrificing the wear capability of metal shoes, and are much easier tofit to the hoof. In particular, a polyurethane plastic such as theproduct described in US. Patent No. 3,214,- 411, issued on Oct. 26,1965, has been found desirable. A material which has been successfullyused is a commercially available product of Mobay Chemical Company,Pittsburgh, Pa., known as Texin 480-A.

The body of the shoe includes a generally arcuate forward portion 12 andthe usual inwardly curving rear portions 14 which are shaped generallyto the contour of a hoof. A protective flange 15 is formed as anintegral upwardly extending part, tapering up and inwardly as shown inFIG. 6, and extending around the forward edge of the shoe, preferablyback around the sides for a substantial distance as shown in FIG. 2.This flange engages around the periphery of the hoof and extendspartially up the outer surface of the hoof to cover the peripheral edgethereof. The rear sections of the shoe are joined by a crossbar 18,preferably including a narrower neck portion 20, which may be cut andtrimmed to provide for shaping and adjustment of the spacing of the rearportions 14. When such trimming is necessary, the separated part of thecrossbar are joined by a split metal ring 22 (see FIG. 10) which isusually known as a hog ring. As will be explained, by drawing this ringtighter, the separated parts of the crossbar can be adjusted toward eachother to fit the rear portions of the shoe precisely to the hoof.

Inside the flange 15, formed in the top of hoof surface of the shoe,there are a number of small cavities 24 and a channel 25 which extendsaround the front and sides of the shoe, generally inward from andcoextensive with the flange 15. This channel has been found particularlyuseful for retaining a quantity of lubricating fluid, such as lanolin orother hoof lubricating compounds, which is beneficial to the hornystructure of the hoof. For example, the fluid can be inserted into thischannel periodically by the use of a hypodermic needle and syringe,since a sufiiciently sharp needle will penetrate the body of the shoewithout harming it.

At the toe of the shoe there is a downwardly extending elongated toecleat 27, and at the toe and along the sides a number of smallerbar-like extensions or ridges 28 form additional gripping surfaces forimproved traction. Under some conditions, it is desirable to incorporateelongated cleats 30, and a number of these are shown extending from thelower or ground surface of the shoe. Where these cleats (or the toecleat) are not desired, they can readily be omitted from the shoe duringthe molding process, simply by plugging the mold cavities for thecleats. Furthermore, the cleats can readily be trimmed by a sharpnipping tool, thereby enabling the shoer to adjust the height of thecleats, as for purposes of correcting an irregular gait tendency of thehorse.

On the ground surface of the rear portions 14 there are pads 32 whichinclude a raised crisscross pattern of traction surface. This type ofconstruction is preferred for front shoes, or for rear shoes where thereis no exceptional demand for good traction. Particularly in those caseswhere additional traction is needed, as with jumping horses, calks 35can be formed in the area of these pads, as shown in the modified formof shoe in FIG. 7. The calks have a tapered prow or front 37 to minimizethe drag that the calks may cause during running. This shoe incorporatesthe small traction ribs 28, but omits the cleats, since experience hasindicated that these usually are unnecessary on the type of shoe whichrequires a raised calk. A section through the elongated calk is shown inFIG. 8.

The shoes are provided with a number of nail holes 40, and the resilientplastic material of the shoe has embedded in it, at the time it ismolded, one or more thin metal retaining plates 42. These plates areformed with apertures corresponding to the nail holes, and are locatedin the sides and toe of the shoe. The plates are out lined in dottedlines in FIG. 2, and are shown in crosssection in FIGS. 5 and 6. Theplate at the toe portion of the structure is in the nature of a thinmetal Washer. The purpose of these plates is to assist in holding theshoes in place when the shoe is in use, because in many instances shoersmay prefer to apply these shoes to the hoof by nails, in accordance withthe conventional and presently known practice with which they arefamiliar.

It should be recognized, as mentioned, that there are a number ofwell-known disadvantages to the use of nails for this purpose. If thenails are not properly applied, they can cause substantial damage to thehoof. One or more nails can be loosened and then forced into the hoofcreating injury, or upon being loosened the nails may eventually permitthe shoe to work loose to the point where it is thrown, with possibleinjury to both the horse and anyone around. It has been found that nailsused to hold shoes as disclosed herein will grip in the apertures in theplates 42, but due to the nature of the material of the body of theshoe, these metal plates can move somewhat in the shoe, with the resultthat there is a possibility for limited shock absorbing movement betweenthe nails and the actual body of the shoe, reducing the tendency toloosen the nails under shock, and reducing the tendency to transmitshock from the nails into the hoof. Therefore, even when applied withnails, it has been found that the shoes disclosed herein havesubstantial advantages over metallic and similar shoes such as disclosedin the beginning of this specification.

The invention also relates to a novel method and apparatus for applyingthe shoes, such as described above, directly to the hoof of the animal,by means of a suitable adhesive. A commercially available adhesive knownas Estain, available from B. F. Goodrich Company, has been suitablyemployed for attaching the shoes to the hoof, without use of nails.Another adhesive which has been found suitable is known as Plibond,available from Goodyear Tire and Rubber Company. Since the adhesivesrequire some time to set, it is desirable to clamp the shoe intoengagement with the hoof for a sufficient time to permit the adhesive toset, after which the clamping structure can be removed.

A novel clamp for this purpose is shown at FIGS. '9 and 10. It includesa front hinge structure provided by a pair of bars 50 which are joinedthrough pins 52 to swinging side clamp members 54. These members haveupwardly and inwardly curved retainer pieces 55 fastened to them, andadapted to extend upwardly around the flange 15' to hold it against thehoof. One of the side members 54 has the retainer bar member 58 attachedto it by a hinge pin 59. The member 58 is hollow, for example by aconstruction of parallel plates or the like, and at its other end thereis an internally threaded block 60 receiving a threaded thumbscrew orbolt 62. The base of this bolt engages the outer side of the other clampmember 54, thereby providing an adjustable arrangement which can squeezethe side members of the clamp around the shoe and against the hoof. Withthe bolt released, the member 58 can swing outwardly and the sides ofthe clamp can in turn swing Open, as shown in FIG. 10, to release clampstructure from the hoof.

In a typical operation, the neck 20 of the crossbar 18 can be cut andtrimmed, if needed, the hog ring 22 inserted and tightened, and theadhesive applied to the bottom of the hoof and/or to the hoof surface ofthe shoe. Preferably, the adhesive is applied to the shoe so that it canbe forced into the small cavities 24, while keeping the adhesive out ofthe lubricating channel 25. If desired, lubricant can be applied to thischannel at the same time, particularly if it is sufficiently viscous toremain in the channel while the shoe is applied.

The shoe is then fitted to the hoof, including tightening of the hogring as necessary, and the clamp is applied and the bolt tightened tohold the shoe in position on the hoof. The side members of the clamp mayinclude one or more cleats 64 which would permit the animal to rest itsfoot on the ground temporarily with the clamp applied. Whether or notthis is desirable will depend to some extent upon the nature andtemperament of the animal, since it is of course necessary to avoidloosening or twisting of the clamp while the adhesive sets. Once theadhesive has set, the clamp structure can be removed, and the shoe willbe bonded to the hoof without the need for nails, thereby eliminatingany of the difiiculties and disadvantages that result from the use ofnails. When it is time to replace the shoe, the shoe can be removed bytrimming, as with a sharp instrument, together with the use of suitablesolvent for the adhesive.

The present invention, therefore, provides novel shoes for hoofedanimals, and methods of applying them, wherein a number of advantagesare attained. The elastomeric material used in the construction of theshoes can readily be made sufficiently translucent to show any stones orother pieces of foreign matter that might work between the hoof and theshoe, and the shoe is flexible enough to allow such material to beremoved. Where the shoes are applied solely through use of an adhesive,all of the disadvantages of nails are eliminated. Where nails are used,the fact that the nail engages the metal retainer plate embedded in theshoe provides a shock absorbing action between the nail and the shoe,and since the head of the nail can be recessed within the body of theshoe, no direct contact will normally occur between the nail and theground.

The shoes are sufficiently resilient to provide shock absorption whichis beneficial to the legs of the animal. In a number of cases, shoesconstructed as described herein have been successfully applied toanimals unable to run with metal shoes, and the usefulness of anexpensive animal has been substantially prolonged. The cleats, inparticular, can be trimmed to different heights to cause the hoof tomove to one side or the other, and thus counteract an unusual gait ortractive pull of the animal. The toe cleat 27, in particular, is furtherbeneficial in that it tends to stabilize the hoof and urges the hoof toclear the ground on the end of the stride. Under hard use, as in hardrunning of race horses, metal shoes will heat due to the abrasion andfriction with the ground. This tends to drive the natural lubricant fromthe hoof, however it has been found that the shoe of synthetic material,as provided herein, does not have this tendency, and in addition thechannel for an external supply of lubricant is provided to furthercondition the hoof.

The flange around the toe of the shoe, in particular, is beneficial inavoiding injury where a gaited horse strikes itself as in forging, crossfiring, or other interferences. The flange covers the sharp edge of thehoof itself, and is sulficiently blunt and soft to avoid cutting. Thestructure of the ground surface of the shoes also is beneficial in that,because of some possible flexing of the shoe, it can clear itself of anycollection of dirt or other foreign matter, and the extended cleats 30can provide substantial shock absorption when the animal is required towalk or run over hard surfaces. The crossbar 18, in addition toproviding for 6 accurate fitting of the shoes, also provides someprotection for the frog of the hoof. In general, particularly withgaited animals, an improved and smooth stride has been observed with theuse of these shoes.

While the methods herein described, and the forms of apparatus forcarrying this method into effect, constitute preferred embodiments ofthe invention, it is to be understood that the invention is not limitedto these precise methods and forms of apparatus, and that changes may bemade in either without departing from the scope of the invention.

What is claimed is:

1. A horseshoe comprising a body of an elastomeric polyurethane plastic,said body including a main supporting member having a generally arcuateforward portion and inwardly curving rear portions shaped generally tothe contour of a hoot, said portions having a hoof surface adapted toprovide the main support for the hoof by fitting of said portionsbeneath the bearing surface of a hoof and also having a ground surface,a connecting bar having opposite ends formed integrally with said bodyand extending between said rear portions, said bar having a sectionadapted to be severed and trimmed to adjust the length of said bar toflex said rear portions toward each other to shape the curving rearportions of the body member into conformity with the shape of a hoof towhich the shoe is fitted, and means for adjusting and holding thetrimmed ends of said bar in adjoining relation beneath the hoof as theshoe is attached to the hoof.

2. A horseshoe as defined in claim 1 including an open channel formed inthe upper surface of said body member and terminating short of theperiphery of said body member and adapted to be located beneath thehorny sole of the hoof for retaining a quantity of lubricating fluidplaced in said channel and to maintain such fluid in contact with thesole of the hoof.

3. A horseshoe as defined in claim 1, including an insert member moldedinto said body member, a plurality of apertures formed in said insertmember and including integral tangs of suflicient rigidity to bearagainst the sides of a nail passing through the aperture of the insertmember to resist movement of the nail out of the body member once thenail has been inserted, and locating means formed on the bottom surfaceof said body member in alignment with said apertures in said insertmembers to align inserted nails with said apertures.

4. A horseshoe as defined in claim 1 including a plurality ofdepressions formed in the upper hoof engaging surface of said bodymember and adapted to receive a self-hardening adhesive for retainingthe shoe on a hoof without nailing.

5. A horseshoe as defined in claim 1, including a plurality of treadmembers formed as protrusions from the bottom surface of said bodymember to provide a ground engaging surface with improved tractioncapabilities on the bottom surface of the shoe.

6. A horseshoe as defined in claim 5, wherein said tread members areconstructed for trimming to different heights according to the need forcompensation of the manner in which the animal places its hoof duringrunning.

7. A horseshoe as defined in claim 1, including a protective flangeextending upwardly and partially over said forward portion at least inthe center thereof to engage the outer surface of the hoof and thus tocover the sharp lower edge at the forward part of the hoof.

8. The method of attaching to a hoofed animal a flexible shoe having anintegral crossbar which can be varied in length to adjust the shape ofthe shoe to the bottom of the hoof, comprising (a) fitting the shoe tothe bottom of the hoof and cutting the crossbar into parts of a lengthwhich brings the sides of the shoe into approximate conformity with thesides of the hoof,

(b) securing the parts of the trimmed crossbar to each other andadjusting the distances between them to retain the adjusted shape of theshoe,

(0) applying an adhesive to at least one of the surfaces of the shoe andthe hoof to which the shoe is pp (d) then clamping the shoe to the hooffor a period suificient to allow setting of the adhesive, and

(e) then removing the clamp to leave the shoe attached to the hoof.

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